The primary objective of Core B (Radiopharmacy) is to provide support to Project 1, Human Studies. Yttrium-90 radiolabeled chimeric T84.66 anti- CEA antibody will be used in Phase I and Phase II clinical trials for colon and breast cancer patients at the City of Hope National Medical Center. Indium-111 radiolabeled chimeric T84.66 antibody will be used for dosimetry purposes. iodine-1`23 rabiolabeled chimeric T84.66 fragments will be used for Phase I imaging studies. The radiopharmacy will support Project 1 by providing expertise and facilities to prepare radiolabeled antibodies and to provide quality control for these reagents. A protocol for large-scale preparation of In-111, Y-90 and I-123 labeled monoclonal antibodies is currently active. As part of its core activity the Radiopharmacy also supports the conjugation of the monoclonal antibody constructs to be used in the clinical trials. The secondary objective of Core B is to provide labeling for clinical development of novel constructs and chelates. In this way, the Core supports project 2 (Bioengineered Antibodies) and Project 3 (Antibody Chelates and Conjugates). The biochemical and radiological stabilities will be determined for these antibody preparations, providing this information for the filing of IND applications.